Mass centering machine



Ap fil s, 1943.

F. w. HAEGER ASS CENTERING MACHINE Filed Aug. 2, 1940 2 Sheets-Sheet 1 3nveritor I glib W272 attorneys April 6,1943, E. W.-HAE'GER 2,315,998

- MASS CENTERING MACHINE Filed Au .-2. 194g 2 Sheets-Sheet 2 Z'Snventor attorneys Patented Apr. 6, 1943 UNITED STATES PATE'N T OFFICE MASS CENTERING MACHINE Frank W; Haeger, Lansing, Mich, assignor'to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 2, 1940, Serial No. 349,388

1 Claim. (01. 73- -53) This invention has to do with improvements in the type of balancing machine disclosed in prior Patent No. 1,761,945 granted June 3, 19 30, to Thomas C. Van Degrift and known as a mass centering machine. In such machines a rough forging,such as a crankshaft forging, is adjustably clamped in a suitable frame provided with end journals, the frame having previously been balanced both statically and dynamically. The frame with the forging in it is then placed in the machine and rotated and the amount and angular location of out-of-balance at each end of the shaft is noted. Thereafter the forging is adjusted laterally in the frame so as to correct for out-of-balance and if a subsequent run in the machine indicates no out-of-balance, centers are drilled in the ends of the shaft. By thus drilling the centers along the axis of rotating balance of the rough forging much less machining is required after finishing the shaft to bring it into balance.

The present invention has to do with a simple indicating mechanism which may be used with this type of machine to indicate the location of out-of-balance and enable the operation to' be performed in less time and at less cost. According to the invention there is secured at each end of the frame in which the shaft is mounted a set of projections, each projection being in line lengthwise with one of the set screws used to adjust the position of the forging laterally in the frame. The projections of each set are spaced axially along the frame and with each projection cooperates a switch controlling a suitable light of distinctive color. The switches are arranged in axial alinement and each set of switches is preferably carried by a support which may be shifted toward or away from the rotating frame. When the forging is clamped in the frame in such position that the assembly of frame and forging is in balance, and the assembly is rotated, each switch is engaged and momentarily closed by its respective lug once during each revolution of the shaft so that the different colored lights are energized in succession. If the forging is out of balance, the assembly of frame and forging will perform a gyratory or wobbling movement with the heavy side of the assembly shifted outward and the light side shifted inward. The result is to cause the lug adjacent the heavy side to energize its switch causing the corresponding colored light to flash while the other lights are not energized. Should the heavy side fall between two of the adjusting screws two of the lugs will be moved outwardly sufficiently to energize their switches thereby lighting the corresponding colored lights while the third light will remain dark. After noting the indication of out-of-balance given by the lights the operator stops the machine and shifts the ends of theshaft laterally in the frameby means of the set screws so as to bring the shaft and frame into rotating balance. The machine is again operated and if out of-balance is still indicated a second adjustment of the position of the shaft is made to bring it into rotating balance. When the forging is so adjusted in the frame that rotating balance is achieved, centers are drilled in the ends of the shaft preferably while in position in the machine.

The described arrangement provides a simple but effective means for indicating the location of ut-of-balance on the type of machine described.

Employing the indicating mechanism described an operator can" mass ce'nter'a greater number of shafts in a given time than with machines equipped with conventional. indicating mechanism.

Further details and advantages of the invention are indicated in the course of the following description.

In the drawings:

Figure 1 is a top plan view of a form of my improved machine. v

Figures 2, 3 and 4 are fragmentary views taken on the corresponding section lines of Figure 1.

Figure 5 is a fragmentary view taken on section line 5--5 of Figure 4. V

Figure 6 is a fragmentary view taken on line 6-6 of Figure 5.

l0 indicates a suitable base at each end of which is provided a horizontal pivot 12 on which is pivoted a support 14 on which is mounted by means of vertical pivot IS a bearing support l8. Movement of supports I4 about pivots I2 is yieldi'ngly resisted by spring pressed plungers 20 as shown in Figure 2. Bearing supports 18 carry at their upper end ball bearing 22 in which are rotatably mounted hollow stub shafts or journals 24 to which is secured a frame 26. In the frame 26 is clamped the crankshaft 28, as best shown in Figure l, or any other part which it is desired to center. The clamping of the crankshaft 28 in the frame is accomplished by duplicate clamping devices arranged at opposite ends of frame 26 each consisting of set screws 30 provided with suitable operating knobs 32 as best shown in Figure 3. One of the set screws 30 of each set is preferably mounted in a clamping member 33 pivoted at 35 and adapted to be locked to a lower fixed clamping member 31 by a pin or catch passing through alined apertures in the clamping members. By withdrawing the pins from the apertures 39, clamping members 33 may be raised to permit removal of the shaft 28.

Preferablythe clamping devices described are adjustable lengthwise of the frame 26 to enable it to receive shafts of different lengths. 7

Frame 26 and journals 24 on which it is mounted may be driven in any suitable manner. I have illustrated in Figure 4 a belt drive 28' from any suitable motor mounted on the base It].

To each end of the frame 26 is secured a member 34 shaped to provide three rings 36. Each of the rings 36 is provided with a lug or cam 38 and each of the lugs 38 is in longitudinal alinement with handle 32 of one of the clamps 36.

There is mounted on the base I adjacent each of the rings 34, a housing 30 containing three microswitches (not shown) whose housings are indicated at 42. The microswitches are of known construction adapted to be closed upon relatively small movement of their actuating plungers 44. Cooperating with each actuator M is a pivoted shoe 46 mounted on a bracket 48 suitably secured to the housing 40. Housing 40 and its connecting parts are slidably mounted on the base Ill; spring 50 normally holding the housing 40 away from the frame. Hand lever '52 is provided to move the housing toward the frame When desired.

j 54 indicates gauges mounted on base it, eac

gauge having its feeler in contact with the periphery of bearing carrier I8. 56, Figure 1, indicates electric bulbs each operated by one of the microswitches 42. It has been found convenfont to give each knob 32 the same color as the bulb which is brought into operation by actuation of a microswitch by the lug which is in longitudinal alinement with the knob.

The machine works as follows:

The operator unlocks and raises clamping members 33, best shown in Figure 3, inserts the crankshaft forging, moves the clamping members 33 into locked position and secures them. He then clamps the ends of the crankshaft in place by adjusting the set screws 33 so as to approximately center the shaft in the frame 26. Next, he rotates the frame and shaft through belt drive 28'. The frame 23 has previously been balanced so that if 'any unbalance exists in the assembly it must be in the crankshaft itself. If any such unbalance exists the assembly of frame and shaft tends to perform a gyratory movement and this causes the assembly and the supports M on which it is mounted to swing from side to side against the resistance of spring pressed plungers 20. In order to determine the location of the unbalance the operator now pulls upwardly on lever 52 to bring the microswitches 42, their actuators 44 and pivoted shoes 43 into operative position. The unbalance ordinarily encountered is usually such as to cause the assembly to oscillate about some nodal point along its axis. The resultant angling of the frame 26 causes one or the other of the three lugs 38 at each end of the frame to engage its shoe 46 and depress plunger 84 of its microswitch 42 thereby energizing the light 56 of the corresponding color. At the same time the gauges 54 give an indication of the amount of unbalance. Should the unbalance lie at an angle between two of the set screws 30 the two corresponding lights will be energized indicating that the unbalance lies between the set screws.

Thereafter the machine is stopped and the shaft 2'3 is shifted in the frame to correct the out-of-balance and the run is repeated and, if necessary, a second correction is made and this is repeated until the shaft is in balanced position in the frame, this being indicated by the fact that none of the lights 56 is energized.

With the crankshaft 23 now properly centered in the frame 25, centers may be drilled in the end of the shaft by any suitable means, preferably without removing the parts from the machine. For this purpose I have illustrated a drill 66 mounted in a suitable holder 62 slidably mounted within hollow stub shafts or journals 24 normally held out of engagement with the end of the shaft by spring 54. When it is desired to drill the end of the shaft, the frame 26 and its shaft are rotated at the desired drilling speed, and compressed air is supplied to cylinder 66 to force piston 38 into locking engagement with the end of holder 32 through jaw clutch l0 and thereafter the tool is advanced against the opposition of spring 64 into contact with the end of the revolving crankshaft. If preferred, provision could be made for holding the frame 26.- stationary while revolving ;the drill but the above arrangeme' t has proven to be satisfactory. 7

Various modifications will occur to those skilled in the art. 1

I claim:

In a balancing machine, the combination of a frame adapted to be rotated, means for'yieldingly mounting the frame so it may be displaced in response to unbalance, means for rotating the frame, spaced means located adjacent the ends of said frame for adjustably supporting a part to be balanced in said frame with its axis substantially parallel to the axis of rotation of said frame, said means comprising adjustable holding devices spaced angularly about the axis of said frame, a plurality of signals, a signal operating assembly, means for adjustably mounting the assembly adjacent the frame so that it may be moved toward; or from operative position adjacent the axis of rotation of said frame, said assembly comprising a plurality of signal operating means, actuators on said frame, each actuator being arranged in longitudinal alinement with one of said holding devices and in the same transverse plane as one of said signal operating means so as. to actuate said means to give a signal when the angular position assumed by said frame while rotating due to unbalance causes said actuator to engage the corresponding signal operating means thereby indicating the angular location of unbalance.

FRANK W. HAEGER. 

